class TCPDump

# File lib/tcpdump.rb, line 57
def self.binary
  'tcpdump'
end

# File lib/tcpdump.rb, line 61
def self.build_command(config)
  cmd = binary
  cmd << option_list(config)
end

# File lib/tcpdump.rb, line 94
def self.get_current_config
  @options
end

# File lib/tcpdump.rb, line 4
def self.initialize
  @options = {
    print_each_packet: nil,         # -A
    print_asdot: nil,               # -b
    set_buffer_size:  nil,          # -B
    exit_after_count: nil,          # -c
    check_file_size: nil,           # -C
    dump_human_readable: nil,       # -d
    dump_c_program_fragment: nil,   # -dd
    dump_decimal_numbers: nil,      # -ddd
    list_interfaces: nil,           # -D, --list-interfaces
    print_link_layer_header: nil,   # -e
    print_ip_numeric: nil,          # -f
    file_filter_expression: nil,    # -F
    avoid_line_break: nil,          # -g
    rotate_seconds: nil,            # -G
    version: nil,                   # -h, --help, --version
    interface: nil,                 # -i, --interface
    monitor_mode: nil,              # -I, --monitor-mode
    absolute_seq_num: nil,          # -S, --absolute-tcp-sequence-numbers
    type: nil,                      # -T
  }
  tcpdump_check
end

# File lib/tcpdump.rb, line 70
def self.option_list(config)
  options_list = '';
  options_list << ' -A' if config[:print_each_packet]
  options_list << ' -b' if config[:print_asdot]
  options_list << " -B #{config[:set_buffer_size]}" if config[:set_buffer_size]
  options_list << " -c #{config[:exit_after_count]}" if config[:exit_after_count]
  options_list << " -C #{config[:check_file_size]}" if config[:check_file_size]
  options_list << ' -d' if config[:dump_human_readable]
  options_list << ' -dd' if config[:dump_c_program_fragment]
  options_list << ' -ddd' if config[:dump_decimal_numbers]
  options_list << ' -D' if config[:list_interfaces]
  options_list << ' -e' if config[:print_link_layer_header]
  options_list << ' -f' if config[:print_ip_numeric]
  options_list << ' -F' if config[:file_filter_expression]
  options_list << ' -g' if config[:avoid_line_break]
  options_list << " -G #{config[:rotate_seconds]}" if config[:rotate_seconds]
  options_list << ' -h' if config[:version]
  options_list << " -i #{config[:interface]}" if config[:interface]
  options_list << ' -I' if config[:monitor_mode]
  options_list << ' -S' if config[:absolute_seq_num]
  options_list << " -T #{config[:type]}" if config[:type]
  options_list
end

# File lib/tcpdump.rb, line 98
def self.print_current_config
  puts @options
end

# File lib/tcpdump.rb, line 32
def self.root_check
  fail 'Must run as root' unless Process.uid == 0
end

# File lib/tcpdump.rb, line 66
def self.set_options(hash)
  hash.each { |k, v| @options[k] = v }
end

# File lib/tcpdump.rb, line 50
def self.tcpdump
  root_check unless @options[:version]
  command = build_command(@options)
  puts "Running command: #{command}"
  system(command)
end

# File lib/tcpdump.rb, line 46
def self.tcpdump_check
  fail 'tcpdump CLI tool should be installed' unless tcpdump_installed?
end

# File lib/tcpdump.rb, line 37
def self.tcpdump_installed?
  ENV['PATH'].split(':').each do |path|
    exe = File.join(path, 'tcpdump')
    return true if File.executable?(exe)
  end
  nil
end